Benthic biogeographic patterns on the deep Brazilian margin

Area of Science:

• Marine Biology
• Oceanography
• Biogeography

Background:

• The Brazilian continental margin (BCM) features deep waters with rich geomorphology and productivity gradients.
• Previous deep-sea biogeographic studies on the BCM were limited by data scarcity and focused on water masses/salinity.

Purpose of the Study:

• To consolidate benthic assemblage datasets and test existing deep-sea biogeographic boundaries (200-5,000 m) on the BCM using faunal distributions.
• To refine biogeographic boundaries by incorporating latitudinal and water mass stratification.

Main Methods:

• Retrieved over 4,000 benthic data records from open-access databases.
• Employed cluster analysis to examine benthic assemblage distributions against established biogeographic schemes.
• Tested alternative classification schemes considering regional variations in distribution patterns.

Main Results:

• Benthic biodiversity-based classification largely agreed with the Watling et al. (2013) scheme.
• Proposed refined boundaries: two biogeographic realms, two provinces, seven bathyal ecoregions (200-3,500 m), and three abyssal provinces (>3,500 m).
• Identified latitudinal gradients and water mass characteristics (e.g., temperature) as key drivers for these units.

Conclusions:

• The study significantly improves the understanding of benthic biogeographic ranges along the BCM.
• Provides a more detailed recognition of the region's biodiversity and ecological value.
• Supports improved spatial management for deep-sea industrial activities on the BCM.